# Postmortem: Removing all users from github.com/trivago

DevFeed: [Postmortem: Removing all users from github.com/trivago](<https://devfeed.tech/articles/postmortem-removing-all-users-from-github-com-trivago-28013.md>)

Original publisher: [Read original article](<https://tech.trivago.com/post/2021-10-05-postmortem-removing-all-users-from-github-trivago/>)

Author: Andy Grunwald Follow

Published: 2021-10-05T00:00:00Z

Content type: opinion

Language: en

Sources: [Trivago](<https://devfeed.tech/sources/trivago.md>)

Topics: [GitHub](<https://devfeed.tech/topics/github.md>), [incident](<https://devfeed.tech/topics/incident.md>), [Post Mortem](<https://devfeed.tech/topics/post-mortem.md>), [Entra ID](<https://devfeed.tech/topics/entra-id.md>), [pull-requests](<https://devfeed.tech/topics/pull-requests.md>), [ci](<https://devfeed.tech/topics/ci.md>), [Deployment](<https://devfeed.tech/topics/deployment.md>)

Tags: [azure](<https://devfeed.tech/tags/azure.md>), [bugs](<https://devfeed.tech/tags/bugs.md>), [culture](<https://devfeed.tech/tags/culture.md>), [engineering](<https://devfeed.tech/tags/engineering.md>), [engineering-culture](<https://devfeed.tech/tags/engineering-culture.md>), [github](<https://devfeed.tech/tags/github.md>), [incident](<https://devfeed.tech/tags/incident.md>), [mistakes](<https://devfeed.tech/tags/mistakes.md>), [post-mortem](<https://devfeed.tech/tags/post-mortem.md>), [postmortem](<https://devfeed.tech/tags/postmortem.md>), [processes](<https://devfeed.tech/tags/processes.md>), [pull-requests](<https://devfeed.tech/tags/pull-requests.md>), [retrospective](<https://devfeed.tech/tags/retrospective.md>), [slack](<https://devfeed.tech/tags/slack.md>), [systems](<https://devfeed.tech/tags/systems.md>)

## AI overview

This blameless postmortem explains how trivago's automatic synchronization between GitHub and Azure Active Directory removed all synced user accounts from the company's GitHub organization. The root cause was deletion of the Azure Active Directory security group controlling access. The group was restored, users were reinvited, and the incident lasted 1 hour and 19 minutes.

## Source excerpt

While engineering, we fix bugs, create new systems, build workflows and establish processes. Our job is to change things. Changing things can involve mistakes that ultimately lead to the failure...